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Table 2 Description of included studies

From: Non-compliance with randomised allocation and missing outcome data in randomised controlled trials evaluating surgical interventions: a systematic review

Characteristic Descriptive statistics n (%) unless otherwise stated N = 82
Type of trial
 Similar surgical procedures 49 (60)
 Substantially different procedures 17 (21)
 Surgical versus non-surgical management 15 (18)
 Surgery versus placebo surgery 1 (1)
Number of centres and operators
 Single centre 48 (59)
 Multi-centre 32 (39)
 Unclear 2 (2)
Operators in single centre RCTs
 Unclear 20/48 (42)
 More than one operator but unclear 3/48 (6)
 Number of operators reported 25/48 (52)
 Median number of operators in single centre RCTs 2
 [25th, 75th centiles] [1, 3]
 (Min, max) (1, 20)
Operators in multi-centre RCTs
 Unclear 26/32 (81)
 Number of operators reported 6/32 (19)
 Median number of operators in multi-centre RCTs 5
 [25th, 75th centiles] [5, 6]
 (Min, max) (4, 701)
Number participants
 Median 108
 [25th, 75th centiles] [65, 200]
 (Min, max) (15, 2522)
Region
 Africa 3 (4)
 America 16 (20)
 Asia 11 (13)
 Australasia 3 (4)
 Europe 43 (52)
 Intercontinental 5 (6)
 Unclear 1 (1)